To evaluate safety and tolerabilty of multiple oral doses of DMP 777 in six different dose levels: to determine PK and PD characteristics of multiple oral doses of DMP 777 ata six different dose levels: to define DMP 777 dosage level necessary to achieve sustained high-level systemic neutrophil elastase inhibion as determined by measurements of circulating PMN-lysate AAPVase inhibition and whole blood urea fragment levels in selectively defined cohort of patients with CF following twice daily (every 12 hours) or three times daily (every 8 hours) oral administration of DMP 777 for 9 days duration. TOTAL: DMP 777-004, A Phase IIA Multiple Dose Escalation Study to Evaluate the Safety Tolerability Pharmacokinetics an Pharmacoknymics of Multiple Doses of DMP 777 in Adult Patients 18 Years of Age and Older with Cystic Fibrosis.